Friday, June 25, 2010

Report Issued on the 2010 Dietary Guidelines for Americans

by Patrick Baker, Editor

On June 15, 2010 the US Federal Government announced the release of the Report of the Dietary Guidelines Advisory Committee on the Dietary Guidelines for Americans, 2010, a solicitation for written comments on the report, and an invitation for testimony at a public meeting to be held on July 15, 2010 in Washington D.C. Links to this announcement, the report, and instructions for submitting written comments or attending the public meeting are available at the Dietary Guidelines for Americans web site (www.DietaryGuidelines.gov).

Federal legislation requires that the most recent edition of the guidelines (last published in 2005) be reviewed, updated if necessary, and published every five years. The current report contains the recommendations of the 2010 Dietary Guidelines Advisory Committee (DGAC) to the Secretaries of Agriculture and of Health and Human Services for use in updating the Guidelines.

In the introduction, the 2010 DGAC report states that two-thirds of the American public is overweight or obese. It goes on to say that "Americans are making dietary choices in a highly obesogenic environment and at a time of burgeoning diet-related chronic diseases affecting people of all ages, ethnic backgrounds, and socioeconomic levels. The DGAC considers the obesity epidemic to be the single greatest threat to public health in this century."

The introduction goes on to discuss the role of diet and physical activity in attenuating the risk of chronic diseases, as well as identifying population groups of particular concern. These include: children, pregnant and lactating women, and older adults.

Dr. Cordain was asked to comment on the report, and stated "I really don't see how these ‘new’ recommendations vary substantially from prior USDA Food Guidelines." Cordain states that the recommendations to consume whole grains and skim milk "obviously vary from the human ancestral diet, and upon closer scrutiny, these two foods are not necessarily healthful."

Dr. Cordain’s cites evidence from his book The Paleo Diet, as well as his and other published research, that whole grain products frequently may contribute to an elevated glycemic load because of the quantity of total grains the USDA recommends (8 ounces per day, equivalent to 8 slices of bread). Wheat in particular is problematic because it contains the storage protein gliadin, shown to increase intestinal permeability in celiac patients as well as in healthy persons.

Cordain notes that increased intestinal permeability promotes passage of a gut borne bacterial substance called lipopolysachharide into the bloodstream, producing a low-level chronic state of inflammation called endotoxemia (see Maelán Fontes’ article on Type 2 Diabetes and Endotoxemia). Endotoxemia likely underlies many chronic disease states, particularly cardiovascular disease and a number of autoimmune diseases, according to Cordain.

Dr. Cordain goes on to say that, "In the U.S. alone, it is estimated that 1 in 100 people or about 3 million US citizens have celiac disease. It is irresponsible to make across-the-board dietary recommendations to the entire population given the high incidence of celiac disease."

Cordain notes that while skim milk is promoted by the USDA because it contains much lower concentrations of saturated fat, it has been shown to be highly insulinotropic – "meaning that it raises blood insulin concentrations, similar to eating candy or a chocolate chip cookie." Dr. Cordain states that, "Work from our laboratory substantiated this effect for both skim and whole milk. In a recent study of young boys, they became insulin resistant after seven days on a high milk diet, compared to seven days on a high meat diet. This study has not been replicated in adults, but there is no reason to believe that the response would vary." Consumption of milk elevates a hormone called IGF-1 - which increases growth in children, resulting in an increased adult stature. However, says Cordain, "it also increases the risk for breast, colon and most particularly prostate cancer."

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